With the progress of computer technology, besides the improvement made in both hardware and upgrading of application functions of software, user-friendliness of operation and use of computers is also a vitally important challenge to the computer industry.
The conventional man-machine interface is designed to make a computer an easily operating tool that helps a user to complete a desired task, and thus, in the respect of the use thereof, the design must be easy to learn, easy to operate, and allowing for precise control of progress of the desired task or data processing. A good man-machine interface must be designed to provide excellent interaction with the users in order to improve efficiency, quality, and even pleasure of using the computer.
In designing the operation flow performed by a user, since most users do not have sufficient knowledge of the computers, the design must be in such a way that a response is provided for each action taken by the user, so that the user can get aware of the computer being processing the action taken by the computer through immediate response. This certainly improves the convenience of operation of computers to most computer users.